scheduler: Remove assert on the exact number of weighers

Since the weighers code is by design pluggable, downstream packagers may have
added additional weigher classes, causing this assert to fail.

Rather than require downstream maintain a patch against this line, the
proposal is to remove it since the asserts after it are sufficient.

Change-Id: I13765fae188af92a2e729dcd14caf981db01acb4
Fix instance_usage_audit_log test to use admin context

Nova V2 API 'os-instance_usage_audit_log' is for admin only
and Nova policy.json has rule for the same But
test_instance_usage_audit_log tests this API as non admin.

This patch fix test_instance_usage_audit_log test to use admin
context.

Also adding some more tests to verify this API with non-admin context.

Closes-Bug: #1387901

Change-Id: I20a477786ef0f3e1132629c4a12af40524e2b09f
virt: introduce types VirtPageSize and VirtPagesTopology

Introduces a new types VirtPageSize and VirtPagesTopology

Work-item: Enhance libvirt driver to report available
           large pages per NUMA node in the host state data

Change-Id: I4a52bd204930245bd0539210a7f703efdeb06542
Partial-Implement: blueprint virt-driver-large-pages
hardware: fix in doctstring the memory unit used

The unit used to handle memory is MiB not KiB

Change-Id: I49de12d0011cff8e4465759d17b502a821bb9740
hardware: introduce VirtNUMATopologyCellInstance

Introduces a new class VirtNUMATopologyCellInstance which extends
VirtNUMATopologyCell used to handle cells of VirtNUMAInstanceTopology
Also this commit make VirtNUMATopologyCell an abstract class.

Work-item: Enhance libvirt driver to report available
           large pages per NUMA node in the host state data

Change-Id: Icac19c17caec98ae31c039a2b22a7c1de546d9a2
Partial-Implement: blueprint virt-driver-large-pages
hardware: make cell instance topology to handle memory pages

Updates VirtNUMATopologyCellInstance to take into account
account pagesize information

Work-Item: Enhance libvirt driver to report available
           large pages per NUMA node in the host state data

Partial-Implement: blueprint virt-driver-large-pages
Change-Id: Ib8772bff16f6ba58a6266a2ef40b9d81b1d7f00a
object: update instance numa object to handle pagesize

Work-item: Enhance libvirt driver to report available
           large pages per NUMA node in the host state data

Partial-Implement: blueprint virt-driver-large-pages
Change-Id: I392bdc45aa3b6b169c1d1bfdada624a16c77c91c
Merge "virt: introduce types VirtPageSize and VirtPagesTopology"
Merge "hardware: fix in doctstring the memory unit used"
Merge "hardware: introduce VirtNUMATopologyCellInstance"
Merge "hardware: make cell instance topology to handle memory pages"
Merge "object: update instance numa object to handle pagesize"
Merge "Fix instance_usage_audit_log test to use admin context"
Merge "scheduler: Remove assert on the exact number of weighers"